Fastening system and associated anchoring part for a seat

ABSTRACT

The invention relates to a fastening system for a seat for attaching upholstery to the foam cushion part of a seat having an anchoring part ( 10 ) which can be attached in anchoring elements ( 16 ) foamed into the cushion part and which for reliable attachment has two web bodies ( 24 ) which delimit between themselves a receiving space ( 24 ) for accommodating a connecting part ( 12 ) in which the upholstery can be attached.

The invention relates to a fastening system and the associated anchoring part for a seat, especially a vehicle or aircraft passenger seat, for attaching upholstery to the cushion foam part of the seat, having

-   -   at least one anchoring part made as a profile strip, which         anchoring part can be connected to the upholstery which for this         purpose acts on at least one connecting part which engages the         assignable anchoring part for producing a strong connection, and     -   at least one interlocking part which can be at least partially         foamed into the cushion foam part and which with two opposing         interlocking elements delimits a clamping channel, engaging         which the anchoring part with its anchoring elements makes         contact with the assignable interlocking elements, by fitting         under them.

EP 0 403 815 B1 discloses a fastening system with a draw rod as the anchoring part for forming the profile from the outside by a covering material as the cushion materials which are covered as the upholstery in upholstered furniture, and similarly upholstered seat parts, consisting of a one-piece extruded plastic profile rod, to which a separately produced sew-on tag is welded tight as the connecting part for its connection to the covering material between the flat profile parts. In the known solution the profile rod has a twin-leg cross-sectional profile with two profile legs connected to each other on their base by a narrow connecting web, and delimit a receiving gap which proceeds from the web for the sew-on tag by its being tightly welded to the adjacent inside surfaces of the two profile legs. The known solution is designed to attach the draw or profile rod to the sew-on tag directly in the cushion foam part of the seat; this can be accompanied by increased mounting effort, and, depending on the foams used, unwanted loosening of the fastening system is possible, especially if a profile rod, elliptical in cross section, as the anchoring part engages an assignable cavity in the cushion foam part.

DE298 21 697 U1 discloses a fastening system for fastening upholstery, in particular the seat covering of a motor vehicle seat, to a foam cushion element which has a foamed-in insertion part which with bow-shaped regions extends over the thickened front edge area of a retaining strip as the anchoring part, which edge area is pointed toward the insertion part, and to which part the edge of the upholstery is attached via a connecting part. A plastic holder which is used as the interlocking part and which extends under the foamed-in insertion part with a lower leg has two legs rising therefrom in the direction to the retaining strip as interlocking elements which on their top ends have inwardly curved holding areas, between which a lengthwise gap penetrated by the retaining strip which is made without interruption is formed as a clamping channel; the gap width is less than the thickness of the thickened front edge area, the legs being made elastic transversely to the clamping channel and the inwardly curved holding regions are used to make contact with the assignable interlocking elements of the anchoring part made as a retaining strip, by fitting underneath.

This known generic fastening system ensures a high level of attachment reliability by way of the foamed-in interlocking parts; relative to the installation height the fastening system as a whole is designed to be geometrically large solely due to the insert part to be foamed in within the profile body of the interlocking part; this is especially disadvantageous if, as applies in the trend of current seat development, the cushion foam thicknesses used for the cushion foam parts are being made thinner and thinner, so that the known solution is limited especially when the respective seat occupant sits down on the rigid parts of the fastening system with flexible cushion foam parts with thin wall regions, this being experienced as uncomfortable by the seat occupant.

On the basis of this prior art, the object of the invention is to develop the known solutions while retaining their advantages, specifically reliable fastening of upholstery materials to cushion foam parts such that especially the installation height is reduced with simultaneously good installation capacity and low production costs. This object is achieved by a seat fastening system with the features specified in claim 1 and an anchoring part used for this purpose according to the configuration of features of claim 9.

In that, as specified in the characterizing part of claim 1, the anchoring part has two web bodies which delimit a receiving space for accommodating the connecting part and which protrude with a definable projection over the actual anchor body of the anchoring part and in the interlocked attached state project out of the clamping channel with its interlocking elements in the direction of the upholstery to be attached, the connecting part is reliably guided in the receiving space of the anchoring part by way of the lengthened web body and is fixed there. As a result of this guidance with the formation of the receiving space, the anchoring part viewed in cross section as a result can be made distinctly geometrically smaller since, as shown in the prior art, it no longer has to accommodate the connecting means at the same time and exclusively, generally in the form of a sew-on tag, but essentially carries out its anchoring function by means of anchoring elements. Because the free end region of the connecting part is guided and held between the web bodies, it is moreover ensured that even for lateral force application via the connecting part the anchoring elements cannot detach from the interlocking elements of the assignable interlocking part. The clamp-like interlocking part can be reliably attached in the foam cushion part at the desired points, especially can be partially foamed in, so that for the anchoring part there is a reliable interlocking possibility which is to be preferred to pure interlocking in the foam material with low holding forces.

The anchoring part used for the fastening system can preferably be made with a total height <10 mm, preferably with a total height of approximately 5 to 7 mm, especially 6.5 mm, so that the fastening system as claimed in the invention can be easily used for even the most thin-walled cushion foam parts without this adversely affecting seating comfort. The fastening system as claimed in the invention can be quickly produced and economically installed so that in this respect the production effort and production costs are reduced. In particular, the anchoring part is designed as an arrowhead; this facilitates engagement with the respective assignable interlocking part, and the interlocking elements of the interlocking part which are supported on the outer periphery of the respective web body are guided in a defined manner, such that unintentional spreading apart of the interlocking elements and opening of the clamping channel are precluded.

Since the two web bodies preferably extend vertically upright on the top of the anchor body with the two anchoring elements, the connecting part is guided in the direction of the cushion in the receiving space, so that folds which are damaging to the connecting part, especially in the entry area to the receiving space, are reliably prevented. To link the connecting part to the anchoring part a so-called intrusion process has proven especially advantageous, as is shown for example for the plastic extrusion profile for example in DE 103 03 358 A1. In the indicated extrusion process the melting point ranges of the plastic materials of the profile body which are used as the anchoring part and the sew-on tag as the connecting part are chosen to be different, such that one plastic material remains essentially stable in shape when the connection is produced under thermal action, conversely the other plastic material penetrates into recesses formed by one plastic material and hardens in the recesses upon cooling. In this way especially high-strength connections can be achieved, in contrast to known welding and/or adhesive connecting processes.

Since the fastening system is very greatly miniaturized, very stiff and highly-stable plastic materials must be used for the anchoring part, by preference acrylonitrile-polybutadiene-styrene graft polymers (ABS) being used, and a conventional polyester material or the like may be used for the making the connecting part.

Other advantageous embodiments of the fastening system as claimed in the invention and of the anchoring part used for this purpose are the subject matter of the other dependent claims.

The fastening system as claimed in the invention will be detailed below using the embodiment as shown in the drawings. The figures are schematic and not to scale.

FIG. 1 shows a perspective view of the fastening system not yet assembled,

FIG. 2 shows a front top view of the fastening system as shown in FIG. 1 with the connection established.

The fastening system as claimed in the invention can be used for a seat, especially for a vehicle or aircraft passenger seat, to attach upholstery (not detailed) on the cushion foam part of the seat. For this purpose, the fastening system has an anchoring part 10 made as a profile strip, said anchoring part can be connected to upholstery which is not shown, for example by sewing it on, the pertinent upholstery acting on the top end of the connecting part 12 which engages the assignable anchoring part 10 for establishing a strong connection. Furthermore, there is an interlocking part 14 which can be foamed at least partially into the cushion foam material which is not detailed and which, with two opposing interlocking elements 16 which have essentially the same structure and delimit a clamping channel 18 which is open to the top, makes contact with the assignable interlocking elements 16 by fitting underneath, the anchoring part 10 engaging the channel from the top with its two opposing anchoring elements 20 (compare FIG. 2).

As shown in FIG. 1, the interlocking parts 14 can be present multiple times for a profile strip which is made straight as the anchoring part 10 and especially the desired interlocking with the anchoring part 10 can be effected in a line at definable distance to each other. To adapt to special contours or curves on the seat the pertinent profile bodies then are formed from a flexible plastic material in order to be able to adapt to altered contours. The two interlocking elements 16 in the direction of looking at the figures are provided on the bottom side with a widened foam-in plate 22 in order to facilitate the bonding to the foam in this way. From this foam-in plate 22 the two interlocking elements 16 extend up in the form of a web and are kinked toward their free end in order in this way to be able to ensure locking from underneath for the interlocking elements 16 of the anchoring part 10. The cross sections for the interlocking elements 16 are in any event selected such that with penetration of the arrow-like anchoring part 10 they can yield accordingly, especially can spread apart from each other, after penetration of the anchoring part 10 via the clamping channel 18 into the interlocking part 14 the two interlocking elements 16 being elastically reset, in order in this way to be able to guarantee reliable interlocking.

The anchoring part 10 on its top has two flat web bodies 24 running parallel to each other, which delimit a receiving space 26 (compare FIG. 2) for holding the connecting part 14 and which protrude with a definable projection over the actual anchor body 28 of the anchoring part 10 and in the interlocked attached state project out of the clamping channel 18 in the direction of the upholstery to be attached. The magnitudes shown in the figures are due to repeated enlargement of the fastening system which basically is designed as a miniature fastening system, the height of the entire anchoring part 10 including the two web bodies 24 being smaller than 10 mm, especially only 6.5 mm. Furthermore provision is made such that the height of the projecting web bodies 24 is greater than or equal to the horizontal distance between one of the web bodies 24 and the outermost end of the adjacent anchoring element 20. The height of the receiving space 26 between pairs of web bodies 24 is essentially equal to the vertical distance between the two outermost ends of one pair of anchoring elements 20. Preferably the distance between the two ends of one pair of anchoring elements 20 is approximately 5 mm and the width of the two web bodies 24 with the receiving space 26 is approximately 1.4 mm. The height of the connecting part 12 can be stipulated accordingly to the thickness of the foam body material used for the seat and the orders of magnitude for the interlocking part 14 are chosen such that in any event the anchoring part 10 with its anchoring body 28 can reliably engage and extend underneath.

In order to ensure good stability, it is moreover provided that the width of the respective web body 24 is essentially twice the width of the receiving space 26 shown in FIG. 2. Furthermore, the figures show that the anchor body 28 is designed as an arrowhead with anchoring elements 20 which point down to either side and which delimit an engagement space 30 between themselves and each respective assignable web body 24 for engaging the assignable interlocking elements 16. In particular, the two anchoring elements 20 are tilted relative to the horizontal by an angle of approximately 45° and for this purpose are set back. Furthermore, it benefits stability when the total width of two web bodies 24 with the receiving space 28 corresponds essentially to the width of the anchoring element 20 measured along a 45° line X which ends at the lowest point of the engagement space 30 (compare FIG. 2). In this way, viewed in cross section, a box system of durable structure is formed with favorably configured force application spaces, for example in the form of engagement spaces 30. The square structure of the plate 22 also contributes to this and to the length of each interlocking part 14 corresponding to its height in the vertical direction (compare FIG. 1). In order to ensure undisrupted engagement of the anchoring part 10 with the interlocking part 14, provision is made such that the height of the clamping channel 18 between the pairs of interlocking elements 16 as far as the top of the foam-in plate 22 is at least slightly greater than the possible engagement height of the anchor body 28 in the clamping channel 18.

In order to achieve good linkage of the connecting part 12 in the receiving space 26 between the two web bodies 24 of the anchoring part 10, a so-called intrusion process is used, as is detailed in DE 103 03 358 A1. The process shown there is characterized especially in that the melting point ranges of the plastic materials of the anchoring part 10 and the connecting part 12 used are chosen to be different, such that one plastic material remains essentially stable in shape when the connection is produced under thermal action, conversely the other plastic material penetrates into recesses formed by the one plastic material and consolidates in the recesses upon cooling. In this way part of the molten or plasticizable plastic material penetrates into the cavities (recesses) of the other plastic material in order to consolidate there with the formation of a positive connection, preferably the plastic material with the recesses remaining unaffected in its structural configuration due to the different melting point range. Weld or adhesive connections as shown in the prior art consequently are not formed in the intrusion solution which is implemented, but rather part of the connection is positively embedded into the plastic material of the other connecting part and in this way is fixed there as a pouring or intrusion process of plastic materials.

The indicated recesses are formed for this purpose by the receiving space 26 of the anchoring part 10 and also by recesses 32 in the connecting part 12 itself, to the extent that they engage the receiving space 26, these recesses 32 of the connecting part 12 being formed preferably by the opening structures of a woven cloth or knit fabric which for this purpose forms the connecting part 12, these recesses 32 also forming a favorable linking point for the upholstery which is not shown and which can be sewn, cemented, clipped, or bonded to the upper end of the connecting part 12. The fastening system as claimed in the invention can be very quickly produced with reference to the anchoring part 10 by the extrusion tool simultaneously forming the anchoring part 10, and the connecting part 12 running into the free end of the receiving space 26 and then in this way forming a strong connection to the anchoring part 10 directly within the scope of the described intrusion.

In the course of forming the fastening system as claimed in the invention, it has proven advantageous in terms of stability to make the anchoring part 10 from an extrudable plastic, especially in the form of polyester, polystyrene, polycarbonate, and acrylonitrile-polybutadiene-styrene graft polymer (ABS) which are well suited for the described application, including their mixture with each other. The connecting part 12 made in the form of a knit fabric is made preferably from a polyester fiber material. 

1. Fastening system for a seat, especially a vehicle or aircraft passenger seat, for attaching upholstery to the cushion foam part of the seat, having at least one anchoring part (10) made as a profile strip, which anchoring part can be connected to the upholstery which for this purpose acts on at least one connecting part (12) which engages the assignable anchoring part (10) for producing a strong connection, and at least one interlocking part (14) which can be at least partially foamed into the cushion foam part and which with two opposing interlocking elements (18) delimits a clamping channel (18), engaging which the anchoring part (10) with its anchoring elements (20) makes contact with the assignable interlocking elements (15), by fitting under them, characterized in that the anchoring part (10) has two web bodies (24) which delimit a receiving space (26) for holding the connecting part (14) and which protrude with a definable projection over the actual anchor body (28) of the anchoring part (10) and in the interlocked attached state project out of the clamping channel (18) with its interlocking elements (16) in the direction of the upholstery to be attached.
 2. The fastening system as claimed in claim 1, wherein the height of the projecting web bodies (24) is greater than or equal to the vertical distance between one of the web bodies (24) and the outermost end of the adjacent anchoring element (20).
 3. The fastening system as claimed in claim 1, wherein the height of the receiving space (20) between pairs of web bodies (24) is essentially equal to the vertical distance between the two outermost ends of one pair of anchoring elements (20).
 4. The fastening system as claimed in claim 1, wherein the width of the respective web body (24) is essentially twice the width of the receiving space (26).
 5. The fastening system as claimed in claim 1, wherein the anchor body (28) is designed as an arrowhead with anchoring elements (20) which point down to either side and which delimit an engagement space (30) between themselves and each respective assignable web body (24) for engaging the interlocking elements (16).
 6. The fastening system as claimed in claim 5, wherein the total width of two web bodies (24) with the receiving space (28) corresponds essentially to the width of the anchoring element (20) measured along a 45° line X which ends at the lowest point of the engagement space (30).
 7. The fastening system as claimed in claim 1, wherein the height of the clamping channel (18) between the pairs of interlocking elements (16) is slightly greater than the engagement height of the anchor body (28) in the clamping channel (18).
 8. The fastening system as claimed in claim 1, wherein the anchoring part (10) consists of an extrudable plastic, especially in the form of polyester, polystyrene, polycarbonate, acrylonitrile-polybutadiene-styrene graft polymer (ABS) or mixtures thereof.
 9. Anchoring part for a fastening system as claimed in claim 1, wherein it has two web bodies (24) which project vertically on the anchor body (28) of the anchoring part, which delimit a receiving space (26) for accommodating the connecting part (12), and which protrude with a definable projection over the anchor body (28), and wherein the connecting part (12) projects out of the receiving space (26) as a flexible attachment plate, a flat woven fabric or knit fabric.
 10. The anchoring part as claimed in claim 9, wherein the connecting part (12) consists of a plastic material, especially polyester, with a melting point which is higher than the melting point of the anchor body (28). 